What is the expected temperature at 15,000 feet ASL in the ICAO standard atmosphere?

In the ICAO standard atmosphere, the lapse rate, which describes how temperature decreases with altitude, is approximately 2°C for every 1,000 feet of altitude gain in the lower layers of the atmosphere up to about 36,000 feet. At sea level, the standard temperature is defined as 15°C.

To determine the expected temperature at 15,000 feet ASL, you would calculate the temperature decrease over that altitude. This would be:

• Starting temperature at sea level: 15°C
• Altitude: 15,000 feet
• Temperature drop: 15,000 feet x 2°C/1,000 feet = 30°C

Now, subtract the total temperature drop from the sea level temperature:

15°C - 30°C = -15°C.

Therefore, the expected temperature at 15,000 feet in the ICAO standard atmosphere is -15°C. This aligns with the characteristics of the standard atmosphere, effectively illustrating how temperature decreases as altitude increases.